Antenna



Sept 1, 1953 E. J. EHRBAR ET AL 2,650,983

ANTENNA Filed May 25, 1950 5 1 j 5 w F\G.5 18

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zysvmmw Patented Sept. 1 1953 ANTENNA Edward J. Ehrbar and Raymond W. Cronshey,

Cleveland, Ohio, assignors to The Radiart Corporation, Cleveland, Ohio, a corporation of Ohio Application May 25, 1950, Serial No. 164,102

5 Claims. (01. 250--33) This invention relates, as indicated, to an antenna; but has reference more particularly to an improved combination of a feeder dipole and exciter coil.

It has heretofore been proposed, as in the Ferris Patent 2,495,579, to provide an antenna structure comprising elongated rod means forming a dipole antenna component adapted to resonate to radio waves of selected frequency, and another component comprising an elongated cage of conducting material of substantially the same length as said rod means and insulated from and enclosing said rod means along the full length of the rod means, and adapted to resonate to radio waves of different frequency, the cage being supported by and inductively coupled to said rod means.

We have discovered, as a result of various experiments, that improved results, particularly in television reception, can be obtained by utilizing a combination of a feeder dipole and esciter coil, similar to that described above, but arranging the exciter coil in parallelism with, but not enclosing the dipole rods. As a result of such rearrangement of the coil and rods, a capacitative coupling of the coil and dipole rod is obtained, which appears to provide improved results, from the standpoint of reception of all wave bands or channels.

Another advantage of such a rearrangement of the coil and rods is that assembly of the parts is greatly facilitated, since threading of the rods through the coil, with its attendant requirement of careful and uniform spacing of all parts of the coil or cage from the rods, is obviated.

The rearrangement of parts, moreover, possesses a still further advantage in that it enables the central portion of the coil to be supported by simple support means, in contrast with the arrangement shown in the Ferris patent, in which no support is provided for the central portion of the coil, and reliance is placed solely on the stiffness or rigidity of the coil to support it in uniformly-spaced relation to the dipole rods.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Fig. l is a front elevational view of an antenna embodying the principal features of the invention;

Fig. 2 is a side elevational view of the antenna,

2 as viewed from the right side of Fig. 1, i. e., in the direction indicated by the arrows 22 in Fig. 1;

Fig. 3 is a fragmentary cross-sectional view, on an enlarged scale, taken on the line 3-3 of Fig. 2;

Pi g. 4 is a fragmentary cross-sectional view, on an enlarged scale, taken on the line 4-4 of Fig.

and

Fig. 5 is a. fragmentary top plan view, on an enlarged scale, as indicated by the line 5--5 of Fig. 3.

Referring more particularly to the drawings, an antenna is shown, comprising a principal component i, an auxiliary component 2, and suitable means for mounting and supporting the components in operative position and in predetermined relationship to each other.

The principal component I preferably consists of a pair of straight rods 3 of electrically-conductive material, such as aluminum tubing, having upturned vertically-extending ends 4, the rods being suitably supported at the medial portions of the component.

The auxiliary component preferably comprises a helically-wound coil 5 of electrically-conductive material, supported in insulated relationship to the rods forming the principal component. For this purpose, buttons of insulating material are provided having head portions 6 and stems of reduced diameter extending into and mounted in the walls of the upturned portions 4 of the rods 3 adjacent the upper ends of these portions of the rods. The buttons are provided with axial recesses into which the inturned ends of the coil 5 extend and are mounted.

The rods 3 are in axial alignment with each other and their inner ends 8 are received in axial recesses 9 in a central mounting member l0, preferably consisting of a cylindrical block of molded plastic insulating material, which may be provided with annular grooves H for decorative purposes.

Self-tapping headed metal screws [2 are provided, which extend through openings [3 in the walls of the recesses 9 and into the end portions 8 of the rods 3, thereby providing a good electrical contact with the rods 3, and at the same time looking the rods against axial displacement from the member I0. The heads of the screws l2 serve to clamp the terminals M of a transmission line IE to the member 10, whereby the rods 3 are electrically connected to such terminals. The transmission line I5 is used to connect the antenna with apparatus such as a television receiver.

The member 10 is also provided with a radially extending vertically-disposed recess or socket [6, for receiving the upper end of a mounting rod or mast I 1. A friction fit is provided between the socket I6 and mast [1.

As previously stated, the auxiliary component comprises a length of metal wire bent to helical form and supported by the buttons 6 in uniformly vertically spaced and insulated relationship to the rods 3. For the purpose of supporting the central portion of the coil 2 in said spaced relation to the rods 3, and prevent any sagging of the coil, the central portion of the coil rests on the member ID, with spaced convolutions thereof secured against displacement from the member H] by means of clips l8, which are secured to the member l by means of screws 19.

The antenna further includes a base 20 of insulating material, into which the lower end of the mast I1 is threaded.

The principal component, consisting of the pair of oppositely extending rods 3 forms a dipole antenna, While the coil 5, which constitutes the auxiliary component, is capacitatively and not inductively coupled with the latter. This capacitative coupling of the components has been found to be highly advantageous, resulting in improved reception over similar arrangements using inductance or inductive coupling. Energy in the high frequency wave band received on the dipole component is transferred directly to the receivin apparatus through the transmission line I5, while energy in the low frequency wave band received on the auxiliary component is transmitted or coupled thence by the capacitative coupling onto the dipole component, and transferred thence through the transmission line I5 to the receiving apparatus,

Assembly of the coil and rods is greatly facilitated, since it is not necessary to thread the rods through the coil, and the proper and uniform spacing of the coil from the rod is effected almost automatically upon mere attachment of the coil to the rods and member [0.

The arrangement, moreover, enables the centrol portion of the coil to be supported by simple support means, such as the clips 18, so that reliance is not placed solely on the tension given to the coil to support it in uniformly-spaced relation to the dipole rods.

It is to be understood that the form of our invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of our invention or the scope of the subjoined claims.

Having thus described our invention, we claim:

1. Antenna structure comprising a central mounting member of insulating material having oppositely opening mounting cavities formed in coaxial alignment therein, a pair of rod-like mempled to said rod-like members, including inwardly extending fingers on said coil adapted to engage in said mounting sockets to support said coil on said rod means, said coil having its axis parallel with but spaced from the axis of said rod-like members.

2. Antenna structure, as defined in claim 1, in which the central portion of said coil is supported on said central mounting member.

3. Antenna structure, as defined in claim 1, in which convolutions of said coil rest on said central mounting member, and clips are provided for securing said convolutions to said central mounting member.

4. Antenna structure comprising an insulating member, a pair of electrically conductive elements supported in axially spaced relationship by said member to form a dipole, a helical coil of electro-conductive material defining a cylindrical cage, said cage being supported at the ends thereof by the ends of said dipole, said cage being completely exterior therefrom and electrically insulated therefrom, means provided on said member and engaging a portion of said cage intermediate the ends thereof to maintain said cage in parallel uniformly spaced relationship to said dipole, and means for connecting a transmission line to said dipole.

5. Antenna structure as defined in claim 4, wherein said cage-engaging means comprise gripping elements disposed in longitudinally spaced relationship on said member, the space between adjacent gripping elements being coincident with the space between adjacent convolutions of said cage.

EDWARD J. EHRBAR. RAYMOND W. CRONSHEY.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 2,415,810 Cohen Feb. 18, 1947 2,495,579 Ferris Jan. 24, 1950 2,503,010 Tiley Apr. 4, 1950 FOREIGN PATENTS Number Country Date 458,602 Great Britain Dec. 23, 1946 644,522 France June 11, 1928 

